This is a single center phase IV prospective investigation of dose individualization approaches for mycophenolic acid, a potent immunosuppressant, in Caucasian and African American renal transplant patients. Pharmacokinetic evaluations including mycophenolic acid AUC, free fraction of mycophenolic acid, plasma concentration of the glucuronide metabolite of mycophenolic acid, are evaluated on 5 occasions over the first 3 months after transplant surgery in Caucasian and African American renal transplant patients. Validated HPLC methods for drug and metabolite concentration and ultrafiltration for the free fraction measurements are being used. Clinical outcomes such as acute rejection and drug side effects will be evaluated for the duratin of the 3 month study period. The individual patient time courses for the mycophenolic acid will be compared to the percentile distribution values for this parameter for a cohort of 150 renal transplant patients followed by 6 months as part of a multicenter study conducted in central Europe. Tests for significant differences for the African American patients will be performed in comparison to the Causasian study patients and to the percentile distribution described above. From this study we hope to learn of any differences in pharmacokinetic behavior of mycophenolic acid in African American renal transplant patients and a dose individualization approach which would reduce risk for rejection further in comparison to empiric dosing strategies.